Can i fix him papers

You may be able to sponsor him for a green card. Please talk to an immigration attorney about this. Whether he is eligible or not will depend on a...

Do I have to file a G 325A form with an I 130 form for my adult child?

Not required. Can include it anyway.

Will there be an issue petitioning for my wife because she has overstayed in the US on her B-2 visa?

The overstay is not a problem for immediate relatives of US citizens which she would be. She may have other issues though. At the very least...

If I take additional evidence to the consular interview, are the originals sufficient? Do I need to bring translations?

Please have the documents translated to English; and ensure that the proper certification is used.

Immigration question

Even if they don't find out which they most likely will, at some point you will be required to disclose it, if you are pursuing further immigration...

Can woman w/ citizenship in US & Poland enter/exit Poland on US passport? Does she need to update Poland Passport before trip?

As a US Citizen you can enter Poland with your US passport for temporary visit and can return to US with US passport. Call the Polish Consulate...

Is it possible for me to migrate with him when his wife file a petition for him?

A separate petition needs be filed for you because there are no derivatives of an immediate relative petition. If the marriage had taken place...

Yes, there could likely be an interview. To verify validity of documents and parental relationship.

Can I apply for naturalization if my green card expires in 3 months? Or do I need to apply for an extension first?

You will not need to get an extension so long as your residency status is valid even beyond the 3 months. A green card may expire but you are still...

With the employment authorization card mentioned "serves as I-512 Advance Parole" can I travel outside U.S. and no issue?

You may travel outside of the US and return with your Advance Parole document, as long as you had no previous permanent bars from the US. Bring...